[RFC bpf-next 2/8] bpf: Run a sockinit program

[Geliang Tang <geliang.tang@xxxxxxxx>]

This patch defines BPF_CGROUP_RUN_PROG_SOCKINIT() helper, and implements
__cgroup_bpf_run_sockinit() helper to run a sockinit program.

Signed-off-by: Geliang Tang <geliang.tang@xxxxxxxx>
---
 include/linux/bpf-cgroup-defs.h |  1 +
 include/linux/bpf-cgroup.h      | 14 ++++++++++++++
 kernel/bpf/cgroup.c             | 24 ++++++++++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/include/linux/bpf-cgroup-defs.h b/include/linux/bpf-cgroup-defs.h
index 7b121bd780eb..aa9ee82f5d20 100644
--- a/include/linux/bpf-cgroup-defs.h
+++ b/include/linux/bpf-cgroup-defs.h
@@ -37,6 +37,7 @@ enum cgroup_bpf_attach_type {
 	CGROUP_UDP6_RECVMSG,
 	CGROUP_GETSOCKOPT,
 	CGROUP_SETSOCKOPT,
+	CGROUP_SOCKINIT,
 	CGROUP_INET4_GETPEERNAME,
 	CGROUP_INET6_GETPEERNAME,
 	CGROUP_INET4_GETSOCKNAME,
diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index 57e9e109257e..a2f58f0d2260 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -57,6 +57,7 @@ to_cgroup_bpf_attach_type(enum bpf_attach_type attach_type)
 	CGROUP_ATYPE(CGROUP_UDP6_RECVMSG);
 	CGROUP_ATYPE(CGROUP_GETSOCKOPT);
 	CGROUP_ATYPE(CGROUP_SETSOCKOPT);
+	CGROUP_ATYPE(CGROUP_SOCKINIT);
 	CGROUP_ATYPE(CGROUP_INET4_GETPEERNAME);
 	CGROUP_ATYPE(CGROUP_INET6_GETPEERNAME);
 	CGROUP_ATYPE(CGROUP_INET4_GETSOCKNAME);
@@ -148,6 +149,9 @@ int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level,
 					    int optname, void *optval,
 					    int *optlen, int retval);
 
+int __cgroup_bpf_run_sockinit(int *family, int *type, int *protocol,
+			      enum cgroup_bpf_attach_type atype);
+
 static inline enum bpf_cgroup_storage_type cgroup_storage_type(
 	struct bpf_map *map)
 {
@@ -407,6 +411,15 @@ static inline bool cgroup_bpf_sock_enabled(struct sock *sk,
 	__ret;								       \
 })
 
+#define BPF_CGROUP_RUN_PROG_SOCKINIT(family, type, protocol)		       \
+({									       \
+	int __ret = 0;							       \
+	if (cgroup_bpf_enabled(CGROUP_SOCKINIT))			       \
+		__ret = __cgroup_bpf_run_sockinit(family, type, protocol,      \
+						  CGROUP_SOCKINIT);	       \
+	__ret;								       \
+})
+
 int cgroup_bpf_prog_attach(const union bpf_attr *attr,
 			   enum bpf_prog_type ptype, struct bpf_prog *prog);
 int cgroup_bpf_prog_detach(const union bpf_attr *attr,
@@ -505,6 +518,7 @@ static inline int bpf_percpu_cgroup_storage_update(struct bpf_map *map,
 					    optlen, retval) ({ retval; })
 #define BPF_CGROUP_RUN_PROG_SETSOCKOPT(sock, level, optname, optval, optlen, \
 				       kernel_optval) ({ 0; })
+#define BPF_CGROUP_RUN_PROG_SOCKINIT(family, type, protocol) ({ 0; })
 
 #define for_each_cgroup_storage_type(stype) for (; false; )
 
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 93b9f404a007..fe294e4d618c 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -1996,6 +1996,30 @@ int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level,
 
 	return ret;
 }
+
+int __cgroup_bpf_run_sockinit(int *family, int *type, int *protocol,
+			      enum cgroup_bpf_attach_type atype)
+{
+	struct bpf_sockinit_ctx ctx = {
+		.family		= *family,
+		.type		= *type,
+		.protocol	= *protocol,
+	};
+	struct cgroup *cgrp;
+	int ret;
+
+	rcu_read_lock();
+	cgrp = task_dfl_cgroup(current);
+	ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0,
+				    NULL);
+	rcu_read_unlock();
+
+	*family		= ctx.family;
+	*type		= ctx.type;
+	*protocol	= ctx.protocol;
+
+	return ret;
+}
 #endif
 
 static ssize_t sysctl_cpy_dir(const struct ctl_dir *dir, char **bufp,
-- 
2.35.3